This proposal is for a parabolic flight campaign that is critical to Technology Readiness Level (TRL) 6 advancement of current TRL 4 reaction sphere prototypes. The technology is similar to single-axis reaction wheels, but can advantageously provide attitude control in all three degrees of rotational freedom for Size, Weight, and Power (SWaP) savings. Reaction spheres will improve the pointing accuracy and stability for small satellite (smallsat) missions requiring long duration imaging and tracking, and for missions experiencing large disturbance torque accumulations. Along with ongoing development efforts, the proposed free-flying experiments in zero-gravity are needed to adequately validate the technology.